# Learning-Free Iris Segmentation Revisited: A First Step Toward Fast Volumetric Operation Over Video Samples

## TL;DR

This paper explores volumetric iris segmentation using the FLoRIN framework, demonstrating significant speed improvements with minimal impact on matching accuracy, and introduces a new iris video dataset for testing.

## Contribution

It applies the FLoRIN volumetric segmentation framework to iris videos and compares its performance with existing methods, showing notable speed gains and robustness on low-resource hardware.

## Key findings

- FLoRIN achieves 3.6 to 10x faster segmentation than traditional methods.
- Volumetric segmentation maintains comparable matching performance.
- Speedup is effective even on low-resource hardware.

## Abstract

Subject matching performance in iris biometrics is contingent upon fast, high-quality iris segmentation. In many cases, iris biometrics acquisition equipment takes a number of images in sequence and combines the segmentation and matching results for each image to strengthen the result. To date, segmentation has occurred in 2D, operating on each image individually. But such methodologies, while powerful, do not take advantage of potential gains in performance afforded by treating sequential images as volumetric data. As a first step in this direction, we apply the Flexible Learning-Free Reconstructoin of Neural Volumes (FLoRIN) framework, an open source segmentation and reconstruction framework originally designed for neural microscopy volumes, to volumetric segmentation of iris videos. Further, we introduce a novel dataset of near-infrared iris videos, in which each subject's pupil rapidly changes size due to visible-light stimuli, as a test bed for FLoRIN. We compare the matching performance for iris masks generated by FLoRIN, deep-learning-based (SegNet), and Daugman's (OSIRIS) iris segmentation approaches. We show that by incorporating volumetric information, FLoRIN achieves a factor of 3.6 to an order of magnitude increase in throughput with only a minor drop in subject matching performance. We also demonstrate that FLoRIN-based iris segmentation maintains this speedup on low-resource hardware, making it suitable for embedded biometrics systems.